In the art of continuous vertical casting of solid or tubular bar products, it is now conventional to provide the external surface of one of the casting dies with a taper and to seat the die in a cooler assembly which has a tapered internal passage receiving the tapered surface of the die. Such an assembly, for example, is shown in my U.S. Pat. No. 4,000,773, issued Jan. 4, 1977 and entitled "Die Assembly For Continuous Vertical Casting Of Tubular Metallic Products." The function of the cooler assembly is to withdraw heat from the die which is subjected to extremely high temperatures from the molten material being utilized to form the casting. In order to obtain maximum heat transfer between the cooling assembly and the die, it is exceedingly important that the engaging tapered surfaces of these parts be in continuous and complete contact with each other. The problem presented by the latter objective is to provide matching or complementary tapers on the outer surface of the die and the inner surface of the cooler. Heretofore, this has been accomplished by cutting the tapered surfaces on a lathe and, to do this, it has been necessary to twice set the lathe cutting tool at an angle prior to cutting the tapers on the two parts. This not only slows down the taper cutting process but furthermore subjects the operation to the risk of cutting tapers on the parts which do not exactly correspond. The latter can result in insufficient heat transfer between the die and the cooler which could cause failure of the die. Since the dies are made from relatively expensive material, premature replacement is costly. In addition, replacement of the dies slows down the casting operation and, in turn, slows down production.
The present invention seeks to avoid the above noted problem by providing novel and improved method and apparatus for cutting exactly matching tapers on interfitting male and female parts so as to ensure, when the parts are interfitted, there will be substantially complete and continuous contact throughout the tapered surfaces thereof. While the present invention is particularly suitable for use in cutting tapered surfaces on a hollow die and a cooler sleeve which receives the die, the present invention will no doubt have applicability elsewhere in situations where exactly corresponding tapers are desired on interfitting male and female parts or in other situations where complementary or matching tapered surfaces are desired.